Author: Nikita Popov Date: 2020-12-23T21:58:26+01:00 New Revision: 759b8c11c398c20f12503356f8aef604e0bf82be
URL: https://github.com/llvm/llvm-project/commit/759b8c11c398c20f12503356f8aef604e0bf82be DIFF: https://github.com/llvm/llvm-project/commit/759b8c11c398c20f12503356f8aef604e0bf82be.diff LOG: [InstCombine] Handle different pointer types when folding gep of null The source pointer type is not necessarily the same as the result pointer type, so we can't simply return the original null pointer, it might be a different one. Added: Modified: llvm/lib/Transforms/InstCombine/InstructionCombining.cpp llvm/test/Transforms/InstCombine/getelementptr.ll Removed: ################################################################################ diff --git a/llvm/lib/Transforms/InstCombine/InstructionCombining.cpp b/llvm/lib/Transforms/InstCombine/InstructionCombining.cpp index 7bde3845522f..8ace625e1fad 100644 --- a/llvm/lib/Transforms/InstCombine/InstructionCombining.cpp +++ b/llvm/lib/Transforms/InstCombine/InstructionCombining.cpp @@ -1859,7 +1859,8 @@ Instruction *InstCombinerImpl::visitGetElementPtrInst(GetElementPtrInst &GEP) { if (isa<ConstantPointerNull>(PtrOp) && GEP.isInBounds() && !NullPointerIsDefined(GEP.getFunction(), PtrOp->getType()->getPointerAddressSpace())) - return replaceInstUsesWith(GEP, PtrOp); + if (auto *PtrTy = dyn_cast<PointerType>(GEPType)) + return replaceInstUsesWith(GEP, ConstantPointerNull::get(PtrTy)); // Eliminate unneeded casts for indices, and replace indices which displace // by multiples of a zero size type with zero. diff --git a/llvm/test/Transforms/InstCombine/getelementptr.ll b/llvm/test/Transforms/InstCombine/getelementptr.ll index 6524c3c03639..f1af3fda79e7 100644 --- a/llvm/test/Transforms/InstCombine/getelementptr.ll +++ b/llvm/test/Transforms/InstCombine/getelementptr.ll @@ -1263,4 +1263,12 @@ define i8* @gep_null_defined(i64 %idx) null_pointer_is_valid { ret i8* %gep } +define i8* @gep_null_inbounds_ diff erent_type(i64 %idx1, i64 %idx2) { +; CHECK-LABEL: @gep_null_inbounds_ diff erent_type( +; CHECK-NEXT: ret i8* null +; + %gep = getelementptr inbounds [0 x i8], [0 x i8]* null, i64 %idx1, i64 %idx2 + ret i8* %gep +} + !0 = !{!"branch_weights", i32 2, i32 10} _______________________________________________ llvm-branch-commits mailing list llvm-branch-commits@lists.llvm.org https://lists.llvm.org/cgi-bin/mailman/listinfo/llvm-branch-commits
